This invention relates to azeotropic distillation. In another aspect, this invention relates to azeotropic distillation of Z-11-hexadecenal. In yet another aspect, this invention relates to the separation of Z-11-hexadecenal/C.sub.16 -hydrocarbon mixtures. In another further aspect, this invention relates to the separation of Z-11-hexadecenal/hexadecenol mixtures. In a still further aspect, this invention relates to the separation of Z-11-hexadecenal, hexadecadiene, hexadecene and hexadecenol mixtures.
Z-11-Hexadecenal is a known pheromone for several insect species. In order to make this compound widely available for use in insect control, economic large scale synthetic conversion processes must be developed. While large scale reactions have been developed which permit the production of large quantities of Z-11-hexadecenal, the initially obtained product may contain reaction by-products, such as, for example, hexadecadiene, hexadecene and hexadecenol, which can be removed from the impure reaction product only with great difficulty. Thus, when it is attempted to purify Z-11-hexadecenal by distillation in the presence of the C.sub.16 -hydrocarbons, hexadecene and hexadecadiene, and/or hexadecenol, co-distillation of such impurities along with the desired aldehyde product is frequently a problem. Therefore, effective and economical large scale processes for the purification of Z-11-hexadecenal are desired.